Cyclists' high-visibility jackets are invisible to modern car safety systems and will not trigger their emergency brakes

• e-mail

High-visibility jackets worn by cyclists, pedestrians, workmen and lollipop men and women can actually make them invisible to modern car safety systems, according to a US study.

All new cars sold in Britain must now be fitted with autonomous emergency braking (AEB) as standard in the aim of reducing the number of collisions and casualties, particularly involving the most vulnerable road users including pedestrians and cyclists.

People, animals and potentially dangerous objects are supposed to be identified by the safety system's camera and radar when travelling at lower speeds in urban environments. It should warn the driver to slow down before automatically applying the brakes to avoid a crash.

However, an alarming study by the Insurance Institute for Highway Safety (IIHS) indicated the systems may have a 'blind spot' for reflective items.

A dummy mannequin dressed in four different outfits; black clothing, a black outfit with reflective strips, a reflective jacket with black trousers, and a white outfit, were tested out on three different models of cars from 2023.

All fitted with AEB technology, a Honda CR-V, a Mazda CX-5 and a Subaru Forester were used in the study with varying levels of illumination tested for each scenario.

The mannequin was moved as if it was crossing the road. For each test the cars travelled at 25mph.

Each time, the Honda and Mazda hit the dummy wearing reflective strips without slowing every time. 

High-visibility jackets worn by cyclists and pedestrians can actually make them invisible to modern car safety systems, according to a new study

A group of young children walking through a park as a group wearing high-visibility vest

A cyclist rides through Sefton Park in Liverpool wearing a high-visibility jacket

The Honda also failed to slow down for the dummy wearing the reflective jacket, in every type of lighting condition.

The Subaru performed the best as it came to a stop in all but one test with it hitting the mannequin wearing reflective strips in very dim light slowing by only 82 per cent. 

'These results suggest that some automakers need to tweak their pedestrian automatic emergency braking systems,' David Harkey, president of the IIHS, said.

'It's untenable that the clothes that pedestrians, cyclists and roadway workers wear to be safe may make them harder for crash avoidance technology to recognise. 

'This is a worrisome blind spot. 

'To make good on their potential, pedestrian detection systems have to work with the other commonly used safety measures.'

Read More

Horror smash sees car plough into cyclist and child passenger in latest crash at notorious junction

Past research has found that AEB systems reduced pedestrian crashes by 27 per cent but it was warned that on dark roads at night, their effect becomes negligible.

In 2022, AEB systems became mandatory on new cars being sold in the UK and EU.

David Kidd, a senior research scientist at the institute, and the study's author, said: 'The placement and motion of reflective strips on the joints and limbs of pants and jackets allows drivers to quickly recognize the pattern of movement as a person.

'Unfortunately, the moving strips didn't have the same effect for the pedestrian AEB systems we tested and probably confounded their sensors.'

Yousif Al-Ani, principal ADAS engineer at Thatcham Research – a UK company specialising in vehicle security and safety, and responsible for setting motor insurance risk ratings - told MailOnline that autonomous braking systems still need fine tuning.

'AEB systems are developed to an ever-evolving industry standard set of test scenarios,' he told us. 

'Many implementation challenges exist including balancing true activations with false positives. 

'There are always differences in real-world performance versus test protocols, as was seen in the recent IIHS study which highlights a particular 'corner case' for camera-only AEB systems. 

'Additional testing is crucial to highlight these shortcomings across different systems and drive continuous improvement. 

'Capturing and quantifying these types of attributes is one of the ways we evaluate vehicle risks within our Vehicle Risk Rating framework to provide automotive risk intelligence to the insurance industry.'

A spokesman for Mazda said: 'Roadway safety for everyone, including those in and around our vehicles, is a top priority for Mazda. 

'Our engineers are continuously working to improve Mazda's crash avoidance systems and are already using these latest IIHS results to further assist us in this work, with special consideration for night-time pedestrian scenarios.'

A spokesperson for Honda told the Times: 'Continuous improvement is a core part of the company's vehicle development process, and we will closely analyse the results of IIHS's recent non-standard pedestrian AEB testing in an effort to enhance future model performance.'

MailOnline has approached Subaru for a comment.